Adjustable shore



Nov. 17, 1931.

L. S.' HOLMBOE ADJUSTABLE SHORE Filed May 26, 1928 INVENTOR jdsfifalmboe.

ATTORNEY ll Z2 6 Patented Nov. 17, 1931 PATENT OFFICE LAWRENCE S. HOLMIBOE, OI OKLAHOMA CITY, OKLAHOMA ADJUSTABLE snonn Application filed Kay 26,

This invention relates to improvements in adjustable shores, a specific purpose being to provide a jacking device that is particularly adapted to shores, and it consists of the constructions, combinations and arrangements herein described and claimed.

An object of the invention is to provide an adjustable shore or shore jacking device by which the final adjustments of a shore, such as used as a prop for ceilings, walls, and the like,,may be made with ease, the arrangement being such that the entire device may readily be manipulated byv a single workman.

Another object of the invention is to provide a clamping and jacking device for shores, one of the outstanding characteristics of which is the provision of pivoted clamping plates which permit an extremely tight grip upon a shore without marring or spoiling the lumber, and a steady increase in the clamping pressure as the load upon the jack ing device is increased.

Other objects and advantages appear in the folowing specification, reference being had to the accompanying drawings, in which,

Figure 1 is a perspective of the improved adjustable shore,

Figure 2 is a perspective view of the clamping and jacking device,

Figure 3 is a perspective View of one of a pair of clamping plates,

Figure 4 is a vertical section of the device as in use, the shore members being shown in elevation, 1

Figure 5 is a detail elevation of a pivoted collar later referred to,

Figure 6 is a detail section on the line 66 of Figure 5.

Although there are several adjustable shores on the market, it appears that workmen usually resort to the common and more or less primitive expedient of driving an assortment of wedges under one end of a shore when any propping is to be done.

A shore, as is commonly known, comprises a strut set endwise as a prop to support a ceiling, wall, or the like, while certain work is being done.

It may be true that adjustable shores or an shore jacking devices have not come into more 1928. Serial No. 280,778.

general use because contractors are usually reluctant to go to any considerable expense for an accessory such as this. It is one of the purposes of the improvement to provide a practical adjustable shore. This device is the acme of simplicity, and being such, lends itself to the roduction in quantities at an inconsiderable cost. After the arts are once assembled they will not readily ecome disassociate-d, thus constituting a feature that will appealto the class of workmen by which it will be used, who are none too careful how they throw things around.

There are several important features in the invention, one of these being the provision of pivoted clamping plates which have out standing advantages developed later on. An-' other rests with the means for making the final adjustment, this doing away with an assortment of wooden wedges usually employed. The two shore members which are used are so tied together by the elements of the jacking device that one workman can handle the apparatus without difiiculty.

Reference is made to the drawings. A pair of shore members 1 and 2 is used. These are known as upper and lower shore members by virtue of the relative positions assumed asil lustrated. There is no encumbrance on the upper shore member 1, thus permitting that shore member to be taken away and another substituted therefor. The lower shore member 2 is more particularly identified with the jacking device because it carries a collar 3 more or less permanently pivoted thereto by means of a bolt 4. That bolt passes through a section of pipe 29 of sufiicient length to make the collar bear against the protruding ends (Fig. 6).

That collar is large enough to admit the shore member 1 quite loosely. It is sufficiently large to admit a flat wedge 5 which is driven into place between the collar 3 and shore member 1 to secure the latter. A chain 6, or other flexible element, connects the wedge with the collar so that the former cannot be lost. It is possible to omit the wedge and rely upon hitting the collar with a hammer in the full line position in Figure 5 for the tightening effect.

dropping out.

A frame, generally designated 7, is the main body of what may be known as a sliding assembly. The frame is capable of limited rocking movement when a load is imposed thereupon, it being then that the pivoted plates which it carries perform a clamping action that increases as the load increases. The sliding assembly differs from the collar 3 in that the latter is not intended to slide, although it does rock on its pivot t as is understood already.

The frame 7 comprises a bridge 8, side arms 9 and upstanding ears 10. The bridge is thickened toward the center as at 30 so that the frame will not bend under pressure and cramp the threads of the thumb screw that it carries. Certain edges of the frame have beads 12 for the purpose of reinforcement and to make the material cast better.

A connector 13 completes the frame. It joins the side arms 9 at points adjoining the bases of the ears 10. The connector is similar in function to the bridge 8. the result of the formation being general rectangle.

The inner surface ll of the connector is made straight to facilitate casting. The low er portion is enlarged at 15 in order to reinforce the pivotal point 16. A. thumb screw 17, mentioned before. ha. a point that bears in a recess 18 in the thickened back of a clamping plate 19. This plate is one of a pair of clamping plates, the other of which is designated 20.

It is at the points 16 and 18 that the pivoting of the clamping plates 19 and 20 occurs. The principle permits the adaptation of the clamping p ates to the plane sides of a shore member so that there will be no cutting into the surface of the lumber or other material. The same principle permits sufficient rocking of the frame 7 so that the foregoing adaptation may take place, and that the wedging action may increase as the load increases. The short edges of the clamping plates are cut out to provide sets of lugs 21 and 22. The confronting surfaces of the clamping plates are serrated at 23 to secure a good grip upon the shore members to which the sliding assembly is applied. The cut out edges of the clamping plates receive the side arms of the frame 9 so that the sets of lugs bear upon the upper and lower edges of the frame. The

lugs are sufiicientlv far apart to permit lim ited play between them and the frame.

These edges of the frame are'not parallel. They diverge in the direction of the ears 1(. the greatest width occurring adjacent to the pivotal point 16. The clamping plate 19 is made to fit the frame at place adjacent to the bridge 8. There is room enough to get the plate 19 in. but after the thumb screw 17 is turned in a bit the lugs 21 can be made to approach sufiiciently close to the diverting edges to prevent the clamping plate from Although the clamping plate 20 has no follower, such as the thumb screw 17. a little care will keep it in place when the sliding assembly is disconnected from a shore member. The straight back of the plate 20 bears squarely and slidably upon the inner surface 1 1- of the connector 13. The point of contact of the thumb screw with the recess 18 provides a second pivotal point.

A wedge 2t, confined by the 1 1, serves to make the final adj nstment of theshore mem her 1' upon being hammered upon. An intermediate rest plate prevents wear and tear uponthe shore member 1 and provides a larger bearing surface for the latter. The upper surface of the plate 25 is serrated at 26 to avoid slipping. It has end lugs 27 that fit in the slots 11 to retain the plate.

A rivet, or other appropriate stop 28, is intended to prevent total withdrawal of the wedge 24 from the slots 11. This stop occurs at the small end of the wedge, and at a point sutliciently far out to provide considerable latitude of movement for the wedge. A nail can be inserted into any one of a number of holes 33 in the small end of the wedge to hold the latter from sliding loose after having been hammered into position. The sides of the wedge are hollowed to save weight without sacrificing strength. Nails orbolts 31 and S2 keep the slidable assembly 7 in a desired location on the shore member 2. preventing the assembly from being used too close to the top and from sliding off when the more members are disassembled.

The operation is readily understood. It is assumed that the shore member 1 (Fig. 1.) bears upon a ceiling, and that the shore member 2 is resting upon a floor or other support (not shown). An adjustment is rst made to stand the apparatus in place. The swinging collar 3 aids in temporarily holding the shore members together. The frame 7 is teen slid up sufficiently far and held by the. thumb screw 17. v

The wet ge 24 is supposed to be withdrawn as far as possible, that is to say, until the stop 28 bears against the adjacent car 10. The workman now hammers upon the large end of the wedge, driving the rest plate 25 and shore 1 upwardly. The load on the upper shore is transmitted through the wedge 24- to the frame 7, thence through the pair of clan'iping plates 19 andv 20 into the lower shore 2.

As the load on the upper shore member 1 is imposed upon the frame 7, the latter will rock slightly, the points 16 and 18 being the centers of a pivotal action. The clamping plates 19 and 20 will ride parallel to the faces of the shore member 2 and this relationship will be preserved during any load, no matter w h y The action is best explained follows: The. application. of the load in the direction of the arrowtA causes an initial turning of the frame 9 at the point 18, both a pivotal and a sliding action taking place on the plate 20 at the point 16. The play between the lugs of the plate 20 and the frame 9, illustrated by the distance B, permits this sliding, and the sliding and pivoting causes the clamping action of the two plates. It is to be noted that as the load increases, there is a sliding between the frame 9 and the plate 20 at the point 16 but no sliding between the plate 20 and the lower shore member 2.

If the latter sliding occurred there would be a tendency to mutilate the surface of the shore member. The application of the load causes a stress on the plate 20 in the direction of the arrows C, but very little or no stress on the plate 20 in the direction of the arrow D. In order that this may be accomplished the foregoing play at B is necessary. Tests have proved pivoted plates to be preferable to rigid plates because the former will bear the greatest load with the least slipping, and with the least effect upon the shore member.

It is obvious that the upstanding cars 10 extend along the sides of the shore member 1 while resting upon the plate 25. They thus retain the upper shore member, and contribute in a large measure to retaining the two shore members while the apparatus is being handled in its loose condition. The swinging collar 3 also assists in that respect. Upon desiring to tighten the collar 3 it may either be hammered upon when in the full line position in Fi ure 5, or the wedge 5 may be inserted as in Figure 1.

It must be borne in mind that the pivoting of the clamping plates 19 and 20 is one of the outstanding features of the invention. The advantages of the construction have been emphasized already. It is possible to clothe the idea in various structural forms, but any one of various modifications can be embodied with the pivotal relationship of the supporting frame and the clamping plates. It is possible to make some substitutions, for instance the screw 17 may be replaced by a wedge, or wedges may be driven upon the frame in such a manner as to constitute the pivotal points for both clamping plates.

While the construction and arrangement of the improved adjustable shore is that of a generally preferred form, it is to understood that a number of modifications may be made without departing from the spirit of the 2. A shore jacking device comprising a frame having a bridge and a pair of side arms which it connects at one end, a connector parallel to the bridge, toward which connector the side arms widen, and enlargements being part of the connector and providing a pivotal point, clamp plates associated with the bridge and connector, both plates having sets of lugs extending over the edges of the side arms, and one of the plates having a recess, a thumb screw operable in the bridge and engaging the recess to form a second pivotal point, a pair of ears upstanding from the side arms adjacent to the connector and being slotted, a rest plate disposed between the ears and having end lugs fitted in the slots, a wedge riding in the slots beneath the rest plate, and a stop at the small end of the wedge to prevent it from coming out.

3. The combination in a jacking device for shoring, of a collar surrounding a shore member, pivoting means adapted to pivotally attach the collar to said member, a slotted member attached to the opposite end of said collar and adapted to contain a wedge-like member, said wedge-like member being adapted to move in its slot beneath the bottom of a second member to elevate the latter.

4. The invention as in claim 3, including holding plates attached to the collar and surrounding the lower shore member and adapted when slightly tilted to effect a clamping action therebetween and carry a great portion of the load on said shore member.

LAWRENCE S. HOLMBOE. 

